Spring friction device



Nov. 3,' 1936. E w wEB 2,059,503 4 SPRING FRICTIN DEVICE y Filed Sept. 22, 1933 2 Sheets-Sheet 1 Q.\\\\\\.`. r///////////////////V////// l.

- Nov; 3, 1936.

Filed Sept. 22, 1935 E. `w.` WEBB 2,059,503

SPRING FRIUTION DEVICE l 2 Sheets-Sheet 2 Patented Nov.l 3, 1936 UNITED STATES SPRING FRICTION DEVICE A l Edwin W. Webb, Chicago, Ill.,` assigner to Standy ard Car Truck Company, Chicago, m., a cor--t poration oi New Jersey Application September 22, 1933, Serial No. 690,534

3 Claims. (01267-9) This invention relates to'spring friction devices l which are particularly adapted for use on railroad car trucks, although they may be used elsewhereif so desired. 5 It is the general object of the invention to provide -a novel and improved spring friction device which can be used to prevent the natural harmonic action of the spring or springs used in and with the device. 1o A further object of the invention is to provide a spring friction deviceafor breaking down or interrupting the natural harmonic action of springs through frictional checks on the action of the springs and toprovide in such a vdevice means. for readily adjusting the frictional resistance oll'ered to the action of the springs.

Another object is to provide an exceedingly simple and inexpensive spring friction device, the major part of which may be used as a replacement for the inner springrof a standard type,l compound coiled spring used on car trucks. The objects and advantages of the invention will more fullyappear from the following description made in connection with the accom- 25. panying drawings, wherein like reference char- Fig. 4L is a vertical section taken through one l of the spring friction devices of the invention; Fig. 5 is a. horizontal section taken on the line 5 5 of Fig. 4l, as indicated by the arrows; w Fig. 6 is a View looking toward the inner side of one of therriction shoes used in the sprin friction devices; 4and Fig. 'l is a. plan View oi the same friction shoe. Referring to the drawings, there are shown in Figs. l, 2, and 3, certain portions of acar truck including the' side frame 8having a lateral opening S extending betweenthe compression and tension members of the side frame, the sides of this opening being formed by columns IIJ.v Oneend of a bolster il workswithin the opening 9 while one end of a spring plank I2 .rests upon :a spring plank seat I3 formed by that portion of the tension member of the side frame betweenthe columns I 0.- 'Of course, the bolster I I and spring plank I2 extend across to the opposite side frame. The ends of the holster Il are provided with roller bearing seats I4 receiving roller hearings l5 supported within roller bearing seats I6V formed in roller bearing plates il'. Each roller bearing plate has jaws I8 which 5 embrace the sides oi Athe columns I to prevent lateral movement of the roller bearing plate Il relative to the side frame. Supporting the roller bearing plate Il from the'spring plank l2 are two compound springs YIll of standard conlo struction and including inner and outer coiled compression springs |917, and mb. Also supporting the roller bearing plate il from the spring plank I2 are two spring friction devices A of the present invention. Y l5 Preferably, the compound I@ and spring friction devices A are set relative to each other at the corners of a. square with the two compound springs l@ being set diagonally relavtive to each other and the two spring friction 20 devices A being set diagonally relative to eac other.

Each spring friction device ll includes a c: lindrical thimble 2d open at one end and havin an inturned ange 2da and an outturnecl ang'e 25 2Gb at its other end. Disposed in spaced relation from the open end of the thimhle 2li is a head 2l having an upstanding cup-like portionv Ela provided with a number of radial lugs 2th forming spring centering devices. A'portion of 3@ the head di joining the cup-like portion 2in .forms a ange 2 ic which is directly opposed from the ange 2th o" the thimhle. A heavy coiled compression spring 2E surrounds the major portion' of the thirnble 2li and reacts hetween the 35 thimble andthe head 2i, one end of the spring hearing against the ange 2th and the other end of the spring bearing against the flange 251e.

Fitting within the thimhle to are a plurality of friction shoes 23 having arcuate outer sur- 4@ faces which engage the inner walls of the thimble. These friction shoes are assembled together vto form a many-part cylindrical shell which envfaces 23a and these surfaces are Vengaged re- 5o spectively by the conical surfaces of trimcated conical upper and lower wedges 2d. The upper wedge surfaces 23a of the friction shoes project downwardly and inwardly, while the lower wedging surfaces 23a project upwardly and inwardly. 55.v

The two wedges 2l oppose each other and are apertured to receive a bolt 25 which projects downwardly through the wedges and loosely through a central opening in the cup-shaped portion 2|a of the head 2l. The head of the bolt 25 bears against the cup-shaped portion 21a of the head 2l and a nut 2E engages the upper screw threaded end of the bolt above the upper wedge 24 and this nut bears against a washer 21 disposed against the upper surface of the upper wedge 25.

Surrounding the bolt 25 between the lower wedge 2E and the cup-shaped portion 2la oi head 2l is a coiled compression spring. 2B, the individual turns of which are closely spaced from each other. The nut 2S is so adjusted on the bolt 25 that the spring 2% is constantly maintained under compression and this spring is capable of but slight further compressive movement until the different turns of the spring engage each other so that the spring becomes solid.

When the spring friction devices A are located as shown in Figs. l, 2, and 3 in a. car truck between the spring plate` i2 and the roller bearing plate il, and used in combination with standard compound springs i9, these spring friction devices act not only to dampen the action of the springs 22 of the spring friction devices to prevent natural harmonic action ci these springs, but they also act to dampen the natural harmonic action of the compound springs I9. As the spring friction devices d. and the springs I9 are placed under .additional compression, each head 2l moves towards its thimble 2li tending to cause the many part shellv formed by the friction shoes 23 to slide relative to the thimble 2G. Pressure applied by spring 28 tending to urge the wedges 24 toward each other, urges the friction shoe 23 radially outwardly from the longitudinal axial center line of the thhnble 2li and longitudinal sliding movement of the shell formed by the friction shoes is resisted h-y their frictional engagement with the inner wall of the thimble 2U. During initial movement oi the head 2i towards the thinihle 2li, the spring 2li may be compressed somewhat further than normally before the shell formed hy the friction shoes Zl slides relative to the thimhle 25. However, the lower wedge 2d against which spring 23 bears will then tend to exert more pressure against the shoes 3 than does the upper wedge 22E and the shell will quickly begin to slide relative to the thimhle- 2G. s the shell slides a condition of moving friction rather than static friction will 'exist and, the @ring 2d will expand toward its originsl position to cause the pressures exerted by the upper and lower wedges 2d against the shoes 23 to approach equality. The spring 28 thus causes the shoes 23 to oler slight resistance to the compressive action of the spring frictionV device il. at all times. This resistance or drag on the compressive movement of the spring friction device interferes with and breaks up the natural harmonic action of the spring 22. and as the compound springs i! can only compress as the springs 22 oi the spring friction devices compress, the; natural harmonic action of these springs I9 will similarly be broken up. After the spring friction devices have been compressed, the springs 28 and wedges 2i acting against the friction shoes 23 still cause the shell formed by these shoes to oer resistance to sliding movement and as the head 2i moves away from the thimble 20 due to the expansion action of the spring friction devices, the friction shoes oier their resistance to this movement so as to prevent the springs 22 and the springs i9 from rebounding in their natural periodic time, thereby causing the rebound action of the springs to be dampened. Also as the springs 22 and I9 have been slowed down in their compressive action due to the frictional resistance oiered by the shoes 23, the natural rebound action of these springs is further dampened. By reason of these facts, much greater stability and easier riding qualities are given to a car having car trucks equipped with the spring friction devices of the invention.

It is not necessary that there be great frictional resistance to the relative sliding movement between the shell formed by the friction shoes 23 and the'thimble 20, in order to effectively dampen the harmonic action of the springs 22 and I9. By adjusting the nut 2S upwardly and downwardly on the bolt 25, the tension exerted by the spring 23 may be adjusted, so as to easily and eiectively adjust the frictional resistance oered to the compressive and expansion action of the spring fricon device through engagement of the outer surfaces of the friction shoes 23 with the inner Wall of the thimble 20.

In my present spring friction device the spring 28 is not designed to assist materially in cushioning the compressive forces tending to compress the spring 22, as was the case in my prior invention above referred to. By reason of the fact that the shell formed by the friction shoes 23 and the thimble 2li are supported from the head 2l entirely by means of the springs 22 and 28 and the head 2l is not guided in its movement to and from the thimble, the head 2l may twist and weave relative to the shell and to the thimble, Without interfering with the proper contact between the friction shoe 23 and the thimble 2). The bolt opening in the head 2l is quite large so that the head 2| may readily tilt or turn relative to the holt Without diiculiy.

The spring friction device of the invention of exceedingly simple and inexpensive construe@ tion and is effective in use for breaking dem".

the periodic action or the springs used in 1 2id, 2li, 2l, and 28 serve as a replacement for the inner spring l da. of a compound spring i9.

It will, of course, be understood that various changes may he made in the form, details, arrangement and proportions of the various parte g Without departing from the scope of the present invention, which generally stated, consists in a device capable of carrying out the objects above set forth and in the novel parts and combinations oi parts disclosed and dened in the appended claims.

The present invention is in part a continuation of my prior application entitled Spring friction device, S.N. 667,159, led April 21, 1933.

What is claimed is:-

1. A spring friction device having in combination, a thimble open at one end, a head spaced outwardly from the open end of said thimble, o, plurality of friction shoes having outer surfaces shaped to engage portions of the inner walls of said thimhle, said friction shs being assembled "10 together within said thimble to form s. many part shell bearing against the inner walls ofsaid thimble, said shoes having upper and lower inwardly projecting wedging surfaces, upper and lower oppositely disposed wedges bearing against I5 said respective wedging surfaces, a spring disposed-between said lower wedge and said head,

. a spring encircling the major part of said thimiziie and reacting between said head and said thimfble. and a longitudinally adJustable member projecting loosely through said head and extending through said upper and lower wedges. said member bearing at one end against said head and at its other end against said upper wedge.

2. A' spring friction device having in combination, a -thimble open at one end, a head spaced outwardly from the open end of said thimble, a plurality of friction shoes having outer surfaces shaped to engage portions of the inner walls of l5 said thimble, said friction shoes being assembled together within said thimble to form a many part shell bearing against the inner walls of said thimble, said shoes having upper and lower inwardly projecting wedging surfaces, upper and lower.

B0 oppositely disposed vwedges bearing against said respective wedging surfaces, a spring interposed between said shell and said head, a bolt passing loosely through said head and projecting through said two wedges. said bolt having a nut screwed 2li thereon and bearing against said upper wedg and acoiled spring interposed between said lower wedge and said head and surrounding said bolt.

3. A spring friction-device having in combination a cylinder open at one end. a plurality of friction shoes having outer surfaces shaped to engage portions of the inner walls of Said cylinder, said friction shoes being assembled together 5 within said cylinder -to form a many part cylindrical shell bearing against the inner' walls of said cylinder, said shoes having upper and lower inwardly projecting wedsing surfaces formed in a circular manner, an upper wedge bearing against l0 said upper wedging surfaces, a lower wedge bearing against said lower ,wedging surfaces, a head spaced outwardly from the open end of said Y cylinder at a substantial distance vaway from said a cylinder', a. neuem spring disposea'between sans l lower wedge and said head and supporting 4said wedge and said cylinder resiliently from said head in such a manner as will permit swinging, and revolving movement of said head relative to said 20 cylinder and a tie rod member extending between said upper wedge and said head and having bearing againstthe upper' part ofsaid upper wedge and the lower part of said head.` 

